It is well known that there have been serious bacterial contamination issues in the recent past in both human food and companion pet food. It would be desirable to prevent bacterial contamination in the fatty sections of dry pet foods and fatty human food. Salmonella bacteria live in the intestines, both human and animal, and meat may become contaminated if animal feces spreads during the butchering process. Seafood, fruits and vegetables can also become tainted by contaminated water. It is well known that there have been serious bacterial contamination issues in the recent past in both human food and companion pet food. However, there are no published methods found to reach commonly found bacteria, e.g. salmonella, etc. in the fat portions of foods utilizing commonly used preservatives.
One reason is that consumers are aware of non-green and natural additives in food, and since the invention of the internet, more people are educated about chemicals used to process their foods that might be retained.
In Pohlman, F. et al., Meat Sci. 2002 April; 60(4):349-56, 0.5% cetylpyridinium chloride (CPC) was applied to beef trimmings either aerobically or under vacuum before grinding. Beef trimmings were inoculated with Salmonella typhimurium then treated with CPC in vacuum or aerobic conditions.
In Chen, X. et al., J Food Prot. 2014 November; 77(11):1882-8, ground chicken was reported to likely have higher microbiological loads than whole carcasses and parts. Five treatments (0.003% chlorine, 0.07 and 0.1% peracetic acid [PAA], and 0.35 and 0.6% cetylpyridinium chloride [CPC]) were evaluated. Results from this study indicated that using PAA as an antimicrobial agent in a postchill decontamination tank to treat ground poultry parts is effective for the reduction of Salmonella. 
In Sharma, C. et al., the authors report the efficacy of lauric arginate (LAE) on Salmonella survivability in ground chicken containing 9.8% fat was determined under refrigerated storage and concluded that, although LAE possesses strong inhibitory (P<0.05) effect against Salmonella in suspension in 0.1% peptone water, no inhibitory (P>0.05) effect on growth of Salmonella was observed in ground chicken at the currently approved levels of 200 ppm.
Kibble and Pet Food
Pet food is a specialty food for domesticated animals that is formulated according to their nutritional needs. Some type of extrusion is commonly used. It generally consists of meat, meat byproducts, cereals, greens, vitamins, and minerals. Biscuit type pieces are called “kibble”. To meet nutritional requirements, pet food manufacturers blend animal fats, e.g. chicken fat, etc., and meals with soy and wheat grains and vitamins and minerals. This yields a cheap, nutritious pellet that no one wants to eat.
The primary ingredients in pet food are byproducts of meat, poultry, and seafood, food feed grains, and soybean meal. Other ingredients may include salt, preservatives, stabilizers, and chilling agents. Kibble generally contains about 10% moisture. The following is the current general method of manufacturing dry pet food (kibble): dry meal is heated with steam, and moisture is added to approximately 25 wt % level; the wet meal is extruded under pressure and cut to size; the kibble is conveyed with air on to a dryer bed at approximately <220° F.; the kibble are dried down to a moisture level of 6 to 8 wt %; the kibble are sifted to remove broken and fines. Also, the kibble may be sprayed sometimes with another wet coating, usually a liquid flavor (“palatant”) that is water-based. It is during drying and sifting steps that contamination where microbes like salmonella strains can be introduced, and this presents a serious problem. Anytime you introduce water/moisture, the probability of introducing pathogens is a concern. The instant invention solves the preservative problem without changing the process with adverse economic effects. The grains, meat, poultry parts, etc. are heated to 250-260 degrees ° F. This step is designed to kill all the pathogens that likely arise from the poultry scraps that can contain salmonella. However, many manufacturers do not have good temperature control. Also, cross-contamination can occur once the kibble is placed into storage bins and dryers. The moisture level out of the extruder can be 20-25 wt %. After the drying step, the moisture level can be 8-10 wt %. The extruder is intended to be the kill step, however because of the moisture level there can be growth from cross contamination in the manufacturing facility. The normal manufacturing procedure is to coat the extruded kibble with fat and then a flavor coating (called a palatant) can be added by spraying. Poultry fat is commonly used as a coating for kibble.
Shelf life of kibble is usually 1 to 1½ years, however the shelf life of the palatant can be much shorter, e.g. possibly three months. If the kibble factory is contaminated with salmonella, the bacteria can fall into the production lines and get packaged into the kibble bags. Dogs are relatively resistant to salmonella and usually do not show signs of illness from eating contaminated kibble. But humans who handle the food or the dog can acquire the bacteria and get sick. This makes dry dog food a potentially hazardous product, one best kept away from people with weak immune systems such as young children and the elderly.
Present kibble products are commonly preserved with potassium benzoate, sorbate or similar. These are water soluble and do not have the ability to penetrate fat and reach any bacteria hiding inside.
Human infections of salmonella have been traced back to contaminated feed. From the CDC website, “Multistate Outbreak of Salmonella Schwarzengrund Infections Linked to Dry Pet Food (FINAL UPDATE)” Posted Sep. 4, 2007, the CDC is collaborating with public health officials in Pennsylvania and other state health departments and the US FDA to investigate a multistate outbreak of Salmonella serotype Schwarzengrund infections in humans.
In. Maciorowski, K. et al., World's Poultry Science Journal, Volume 60, Issue 4, December 2004, pp. 446-457, the authors report that transmission of food-poisoning salmonellae in the poultry industry is often associated with a contaminated feed supply.